WO2020107862A1 - Economical high-strength fast-cured grouting material and grouting reinforcement method for soft rock tunnel - Google Patents

Abstract

An economical high-strength fast-cured grouting material, comprising an ordinary silicate cement, a fast-cured sulfoaluminate gelatinizer, and water. The ratio of the mass of water to the total mass of the ordinary silicate cement and the fast-cured sulfoaluminate gelatinizer is 0.46 : 1; the mass ratio of the fast-cured sulphoaluminate gelatinizer to the ordinary silicate cement is (0.67-1.5) : 1; the initial setting time of the grouting material is 40±5 min; and the average compressive strength of a cube after 4h of solidification is equal to or greater than 10 MPa. The grouting material has the advantages of fast slurry setting speed, simple preparation, high strength, and fast curing, and meets the rapid construction requirements of soft rock tunnels. Also disclosed is a grouting reinforcement method for a soft rock tunnel.

Description

Economical high-strength fast-hard grouting material and grouting reinforcement method for soft rock tunnel Technical field

The invention belongs to the technical field of construction engineering construction, and relates to an economical high-strength fast-hard grouting material and a grouting reinforcement method for a soft rock tunnel.

Background technique

my country is already the country with the largest tunnel project, the largest number, and the fastest construction speed in the world. By the end of 2017, 14,040km/15,181 highway tunnels had been completed, and by the end of 2017, 15,781km/14,700 railway tunnels had been completed.

The central and western regions are dominated by mountains and heavy hills, and the terrain and geological conditions are complex and changeable, and the development of transportation will inevitably encounter a large number of tunnel projects. With the improvement of tunnel construction standards and construction scale, the safe and efficient crossing of high-stress soft rock areas is facing great challenges, especially when crossing weak and loose broken rock layers, the problem of large deformation of high-stress soft rock is outstanding. The existing tunnel theoretical methods and construction The technical level can no longer meet the needs of engineering disaster prevention and mitigation.

According to the different objects and purposes of grouting, grouting in tunnels can be divided into five categories: grouting in landslides, grouting in tunnels, grouting for foundation reinforcement, grouting for stratum reinforcement, and grouting for anchors. Among them, formation grouting and anchor reinforcement (such as pressure anchor) are the most effective and common engineering measures to control large deformation of weak and loosely broken formations. Therefore, the performance of the slurry is particularly important for the tunnel grouting project. The grouting material is the key to strengthen the weak and loose broken rock to form the reinforcement ring and bearing arch and provide the anchoring force of the bolt. In the design of grouting engineering, the choice of slurry is an important part, which directly affects the quality of grouting and the cost of the project. Due to the different purposes and requirements of grouting, the slurry used should also be different. In the past, the common grouting material for tunnel engineering was ordinary Portland cement paste. The setting time of this cement paste (water-to-binder ratio is 0.5) is often greater than 5h. According to the normal process of the tunnel, the tunnel has been blasted once. Due to the poor structural stability of the initial support of the tunnel, settlement and deformation often occur under the additional load of self-weight and blasting disturbances, and many of them can reach 100-200mm/d. At this time, there is no or only a small amount of cement slurry filled around the anchor rod The strength and grip strength, the anchoring force of the anchor rod, the suspending effect on the initial support and the squeezing and strengthening effect on the surrounding rock cannot be effectively played in time, the surrounding rock and the initial support are emptied, and the overlying rock mass is lost Supporting constraints, due to the low cohesion of the soft rock, it is difficult to overcome the additional load caused by the self-weight and construction disturbances, causing the rock mass of the arch to slide down and loosen, which in turn causes the loose area of the arch to expand and the anchor rod to be anchored The force effect cannot be exerted in a timely and effective manner, the stability of the initial support structure further deteriorates, and the initial support failure and damage problems such as steel frame twisting and breaking, shotcrete cracking, etc., aggravate the occurrence of large deformation disasters. Therefore, the prevention and control of large deformation tunnels are often very difficult and difficult to achieve results. Therefore, for the prevention and treatment of large deformation disasters in weak and loosely broken stratum tunnels, the grouting materials commonly used for stratum reinforcement and anchor reinforcement have the following deficiencies:

(1) The early strength is low, and the surrounding rock can not be strengthened in time and the anchoring force of the anchor rod can not be provided in time. Under the action of frequent construction disturbances (especially blasting vibration), the initial support is prone to settlement and deformation, and the surrounding rock is emptied and then pulled The overlying surrounding rock is loose, causing large deformation disasters.

(2) The slurry coagulation speed is slow, and it is easy to be diluted and lost under the action of groundwater, resulting in poor grouting quality.

(3) The design water-binder ratio is unreasonable. W/C = 1:1 too thin cement slurry is not uncommon.

(4) The on-site dosage of tunnel grouting is inaccurate. For grouting materials with complex grouting materials (especially excessive admixtures), it is easy to leak or repeatedly add some admixture, and the process is complicated and difficult to promote.

(5) The effect is minimal and the reaction is obvious. For soft rock, the ordinary portland cement paste commonly used in tunnels not only does not have the desired effect, but the reinforcement or anchoring effect is very small. It is also soft due to its too thin water-cement ratio and slow setting speed. After long-term infiltration of the rock, the softening effect is obvious, which increases the load of surrounding rock over the tunnel and exacerbates the softening deformation of the surrounding rock of the tunnel.

It can be seen that the development and application of weak and loose broken strata to meet the grouting requirements of large deformation tunnels in complex construction environments, and the simple and practical mixing ratio, strong operability and excellent performance of grouting materials are very important.

Summary of the invention

The purpose of the present invention is to provide an economical high-strength fast-hard grouting material and a grouting reinforcement method for soft rock tunnels. The grouting material has the advantages of fast slurry setting speed, easy preparation, high strength and fast hardening, and is suitable for soft rock tunnels Demand for rapid construction.

To achieve the above objectives, the present invention adopts the following technical solutions:

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water; the quality of water is the same as ordinary portland cement and fast-hardening sulfoaluminate cement The total mass ratio is 0.46:1, the mass ratio of fast-hardening sulfoaluminate cement and ordinary portland cement is (0.67～1.5):1; the initial setting time of the grouting reinforcement material is 40±5min The average compressive strength of the cube after solidification for 4h is ≥10MPa.

Among the above economical high-strength fast-hard grouting materials, the fast-hardening sulfoaluminate gelling agent is fast-hardening sulfoaluminate 425# cement.

In the above economical high-strength fast-hardening grouting material, the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is (1 to 1.5): 1.

In the above economical high-strength fast-hardening grouting material, the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is (0.67~1): 1.

Among the above economical high-strength fast-hardening grouting materials, the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is (0.67～0.9): 1.

Among the above-mentioned economical high-strength fast-hardening grouting materials, the mass ratio of fast-hardening sulfoaluminate cement to ordinary portland cement is 1.5:1.

A grouting reinforcement method for soft rock tunnels, the special feature is: after excavation of a soft rock tunnel by a footage, the first shot of concrete, erection of steel arch, and through the advance grouting small pipe, circumferential radial pipe and lock The foot anchor pipe reinforces the surrounding rock; the advanced grouting small pipe, the circumferential radial pipe and the locking foot anchor pipe are filled with the economical high-strength fast-hard grouting material according to any one of claims 1-6 ; The grouting pressure of the leading grouting small pipe is 1.0～3.0MPa, the grouting pressure of the circumferential radial pipe is 1.5～5.0MPa, and the grouting pressure of the lock foot anchor pipe is 0.5～1.0MPa, to achieve short time interval Excavation construction.

Among the above grouting reinforcement methods for soft rock tunnels: the soft rock tunnels are excavated by mechanical and/or weak blasting construction methods.

Further, for the grouting engineering of soft surrounding rock tunnels, the main anchor support can be divided into advance ducts, circumferential radial ducts and locking foot anchor pipes according to the location of the installation. The advanced grouting catheter, the circumferential radial catheter and the locking foot anchor tube involved in the present invention all belong to the hollow tube type anchor rod, and the anchoring method is adhesive anchoring. Because the role of anchors (pipes) in the soft surrounding rock tunnels has different emphasis, the grouting pressure parameters are different. For the advanced grouting pipe, its main role is to ensure the stability of the excavation face by pre-reinforcing the surrounding rock in front of the palm face. The grouting pressure (final pressure) is generally between 1.0 and 3.0 MPa; The main function of the grouting pipe is to fill the cracks of the soft surrounding rock through the grouting material, improve the integrity of the rock mass, strengthen the surrounding rock, the grouting pressure is large, and depending on the formation gap, the final pressure is generally between 1.5 and 5.0 MPa; The main function of the lock foot anchor pipe is to control the settlement of the arch foot of the supporting structure, the grouting pressure is relatively small, and the final pressure is generally between 0.5 and 1.0 MPa, that is, the anchor hole and the rod body are filled and compacted.

Further, the main application environment of the grouting material related to the present invention in the field of tunnel engineering is: weak, loose, broken and weakly cemented strata, and it is highly likely that large deformation and collapse will occur due to tunnel excavation, blasting vibration and construction disturbance The surrounding rock passage of engineering disasters. Under the lithological conditions of this type of tunnel, it is recommended to use the high-strength fast-hard grouting material of the present invention for all anchor grouting materials. Ordinary grouting materials can be used in the section anchors with good rock mass integrity and not easy to cause large deformation disasters. Under the premise of ensuring the stability of the tunnel structure, the project cost is minimized to achieve the safety and economy of project construction aims.

Compared with the existing grouting material, the water-binder ratio used in the present invention is 0.46:1, and the mass ratio of fast-hardening sulfoaluminate cement to ordinary portland cement is (0.67～1.5):1, with components It has the advantages of simplicity, remarkable effect, and easy on-site implementation, and has the following excellent performance:

(1) High-strength and fast-hardness: 4h compressive strength>10MPa; in view of the characteristics of large deformation disasters in weak and loose broken stratum tunnels, the high-strength and fast-hardening properties of stratum grouting reinforcement and bolt grouting reinforcement have been fully realized, and the reinforcement and Suspension effect, through the actual application of the Weizhai Muzhailing tunnel on site, the effect is extremely significant.

(2) Good fluidity: the initial setting time is 40±5min, simple and practical, and easy to operate. The grouting material of the present invention uses fast-hardening sulfoaluminate gelling agent and ordinary portland cement as the cementing material, wherein the fast-hardening sulfoaluminate gelling agent achieves the purpose of early strength and fast hardening, ordinary portland cement Instead of retarder to control slurry flow and setting time, at the same time, the addition of ordinary Portland cement can greatly reduce the amount of fast-hardening sulfoaluminate gelling agent, which is economically significant; the tunnel site feeding and mixing are simple and the operability is strong , Can greatly improve the accuracy of ingredients and grouting efficiency.

(3) Good penetration and high calculus rate. The grouting material involved in the present invention can be fully pressed into the surrounding rock joint cracks, and the stone formation rate is high, which can effectively play the role of strengthening surrounding rock.

(4) No external admixture, easy to prepare and easy to implement on site.

The present invention is directed to a large deformation disaster that occurs during the construction of a weak and loose stratum tunnel. By combining two types of cement with different properties, a novel high-strength fast-hard tunnel grouting material is trial-produced. The grouting material makes full use of the performance advantages of the two kinds of cement, and has simple components and no external admixture. When used on site, the process is simple and the operation is convenient. The actual application has been carried out through outdoor slope tests and on-site tests in the tunnel, and the effect is extremely significant. It has effectively controlled the large deformation disasters such as cracking and spalling of the soft rock tunnel concrete, twisting and breaking of the steel frame, and initial support intrusion limit. It can be widely promoted and applied . In the selection of grouting pressure parameters, for the lock foot anchor rod, a small grouting pressure (<1.0MPa) is used to fill the anchor hole and the rod body with slurry, which can quickly provide a higher gripping force and improve the anchor rod. The anti-pulling performance and the strength and rigidity of the anchor rod, and the advanced grouting pipe and the circumferential radial grouting pipe use a larger grouting pressure (≥1.0MPa), which can be under the action of a thicker grouting seal layer. The slurry is hydraulically pressed into the joint cracks of the soft surrounding rock to quickly form a reinforcement ring to improve the cohesion of the surrounding rock and the integrity of the rock mass.

BRIEF DESCRIPTION

FIG. 1 is a schematic diagram of the compressive strength of the grouting material of the present invention at the age.

FIG. 2 is a schematic diagram of the flexural strength of the grouting material of the present invention at the age.

detailed description

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear, the following describes the present invention in further detail with reference to the diagrams. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention.

In the present invention, ordinary portland cement and fast-hardening sulfoaluminate gelling agent are selected as raw materials for slurry proportioning. Through the single factor control test and the durability strength test, the high-strength fast-hardening grouting material is optimized to be constructed, and the grouting parameters obtained from the indoor anchoring grouting mix ratio test are used for the optimization test. For example, put into practical application.

The economical high-strength fast-hardening grouting material of the present invention includes ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water; wherein, the quality of water is the same as ordinary portland cement and fast-hardening sulfoaluminate cement The total mass ratio of the coagulant is 0.46:1, and the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is (0.67～1.5):1. The fast-hardening sulfoaluminate gelling agent is fast-setting sulfoaluminate 425# cement.

Preferably, the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is 2:3.

Preferably, the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is 1:1.

Preferably, the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is 3:2.

The preparation method of the above-mentioned high-strength fast-hardening grouting material is that the fast-hardening sulfoaluminate gelling agent and the ordinary portland cement are uniformly mixed according to the proportion, and then the water is added to mix evenly. Among them, the mass ratio of water to fast-hardening sulfoaluminate gelling agent is 0.46:1, and the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is (0.67～1.5):1.

Example 1

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water. Among them, the water-binder ratio is 0.46:1, the mass ratio of fast-hardening sulfoaluminate gelling agent and ordinary portland cement is 0.67:1, and the grouting material prepared by this ratio can meet the needs of weak carbon The load-bearing strength requirements for the grouting of calcareous siliceous slate with a thin layer of high-quality phyllite.

Example 2

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water. Among them, the water-binder ratio is 0.46:1, the mass ratio of fast-hardening sulfoaluminate gelling agent and ordinary portland cement is 1:1, and the grouting material prepared by this ratio can meet the needs of weak carbon The load-bearing strength requirements for the grouting of calcareous siliceous slate with a thin layer of high-quality phyllite.

Example 3

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water. Among them, the water-binder ratio is 0.46:1, the mass ratio of fast-hardening sulfoaluminate gelling agent and ordinary portland cement is 1.5:1, and the grouting material prepared with this ratio can meet the needs of weak carbon The load-bearing strength requirements for the grouting of calcareous siliceous slate with a thin layer of high-quality phyllite.

The preparation method of the grouting material of the present invention is to mix the fast-hardening sulfoaluminate gelling agent and the ordinary portland cement according to the ratio uniformly, and then add water to mix uniformly. Among them, the water-binder ratio is 0.46, and the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is (0.67～1.5):1.

Further, the grouting parameters obtained in combination with the indoor anchor grouting mix ratio test are shown in Table 1. The side length of the test piece is 40 mm, the span is 100 mm, and the loading speed is 50 N/S.

Table 1 Experimental data of the mix ratio of the new grouting material of the present invention

From Table 1, Figure 1 and Figure 2, we can see that for the grouting material with the same mixing ratio (W/C=0.46), the setting time increases with the increase of the ordinary cement content, and the test pieces can reach 10MPa after 4h The above compressive strength, and the compressive strength of the test piece gradually stabilizes with time. In addition, by adjusting the ratio of fast-hardening sulfoaluminate gelling agent and ordinary Portland cement, the three kinds of slurry optimized and selected can meet the two indexes of fluidity and high-strength fast-hardening.

The mixing ratio of Example 3 was selected for on-site sampling test. The specimen size was 70.7mm×70.7mm×70.7mm, using mechanical agitation, the pressure tester model was HYZ-300.10 type, and the loading speed was 1.3kN/S. The results are shown in Table 2.

Table 2 Example 3 Mixing ratio grouting material field sampling strength test record table

It can be seen from Table 2 that in the field sampling test of the mixing ratio grouting material in Example 3, its compressive strength increased with the increase of the curing time of the test piece, and the compressive strength of 30 MPa could be reached in 28d. It should be noted that the average compressive strength of the test piece is calculated as follows: if one of the six measured values exceeds ±10% of the six average values, the data is deleted and the remaining compressive strength is averaged The number is taken as the final average data; if there are still recorded data exceeding the average ±10% in the remaining five test values, the test result of the test block is invalid.

The grouting material for slope anchor rods was used for the grouting and pullout test of the slope anchoring material of Example 3, and the test results are listed in Table 3.

Table 3 Anchor rod pullout test results

Anchor number	Type of slurry	Diameter (mm)	Length (cm)	Age	Anchorage (kN)
1	Ordinary Portland cement paste	φ42	400	7d	64
2	Example 3	φ57	300	4h	232
3	Example 3	φ57	400	4h	259
4	Example 3	φ57	600	4h	309
5	Example 3	φ76	500	4h	399
6	Example 3	φ76	600	4h	480
7	Example 3	φ76	700	4h	502

As shown in Table 3, the anchoring effect of the new grouting material involved in the present invention is much higher than that of common ordinary Portland cement paste, and its 4h pull-out force is about 7 days of ordinary Portland cement paste 4 times the pulling force. At the same time, its anchoring force increases as the diameter and length of the bolt increase. It can be seen that the new grouting material of the present invention achieves the purpose of high-strength and fast-hardness test. The anchoring effect is extremely remarkable, which meets the requirements of engineering engineering to prevent large deformation of soft rock tunnels. And because of the simple and practical mixing ratio and strong operability, there are significant Promote application value.

Example 4

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water. Among them, the water-binder ratio is 0.46:1, and the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is 1.2:1.

Example 5

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water. Among them, the water-binder ratio is 0.46, and the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is 0.9:1.

Example 6

An economical high-strength fast-hardening grouting material, including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water. Among them, the water-binder ratio is 0.46:1, and the mass ratio of fast-hardening sulfoaluminate gelling agent to ordinary portland cement is 0.8:1.

Since the performance of the slurry is particularly important for the grouting engineering of the tunnel, the present invention is aimed at the grouting requirements of soft rock large-deformation tunnels, and is closely combined with the tunnel construction process, and fully considers the tunnel as an anchor (pipe) (including grouting) to The time required for the next cycle of blasting and excavation (approximately 4 hours) requires the new grouting slurry involved in the present invention to provide greater strength and anchoring force in 4 hours (laboratory index is compressive strength> 10 MPa), which disturbs the construction (Especially blasting vibration) In the process, the surrounding rock around the tunnel can form a reinforcement ring to form a bearing arch; at the same time, the anchoring force of the anchor rod can play a role, giving a tensile force to the steel frame and shotcrete to prevent the initial support under the effect of blasting vibration Settlement deformation occurs, and the surrounding rock is emptied, giving the surrounding rock room for traction deformation. Furthermore, considering the time required for feeding, mixing, pumping and cleaning the grouting equipment during on-site grouting in the tunnel (about 40 min), the initial setting time of the grouting slurry involved in the present invention is required to be 40±5 min. Therefore, the two qualitative and quantitative control indicators of the grouting material involved in the present invention are:

(1) High strength and fast hardness: 4h compressive strength>10MPa;

(2) Good fluidity: the initial setting time is 40±5min. The initial setting time is measured by Vicat in accordance with the national standard method.

Based on the above two basic indicators, at the beginning of the test, the present invention was used for various types of cement (Portland cement, ordinary Portland cement, fly ash Portland cement, composite Portland cement, sulfoaluminate cement, fast Hard sulfoaluminate gelling agent, iron aluminate cement, expansive cement, etc.), admixture (fly ash, alumite), admixture (water reducing agent, early strength agent, retarder, expansion agent) The basic performance has been meticulously investigated and analyzed. Through single factor test, orthogonal test and expansive test, up to 500 basic tests have been carried out on various types of cement, and finally optimized and screened to produce simple, easy to operate, high strength, fast and hard, and price Economical, good permeability, high grouting rate and mixing ratio. Finally, the actual application was carried out through field tests in outdoor slopes and tunnels, and the effect was extremely significant. It effectively controlled the large deformation disasters such as cracking and spalling of the soft rock tunnel concrete, twisting and breaking of the steel frame, and initial support intrusion limit, which can be widely promoted and applied It is very popular in other tunnel projects, slope engineering, water conservancy projects, and foundation pit projects.

The three-step excavation method is taken as an example to introduce the on-site implementation scheme of the grouting reinforcement material of the present invention used in the construction of soft rock tunnels:

(1) Step up construction

First, excavate up the steps. After excavating one foot, the early-strength concrete with initial spraying of 3 to 5 cm shall be applied to the excavation surface. According to the weathering, looseness and spalling degree of the surrounding rock, the thickness of the initial sprayed concrete may be appropriately thickened as The sealing layer of the subsequent grouting work; then the stepped steel arch is erected, and according to the site conditions, it can be used for the advance grouting duct, the radial radial grouting duct and the locking foot anchor pipe in stages or at the same time, and inject The grouting material of the invention is then hung with a reinforcement mesh; finally, the concrete is sprayed to the designed thickness to form the upper initial supporting structure.

(2) Middle step construction

Under the support of the upper primary lining, the middle steps are excavated on both sides, and the core soil part of the middle steps is reserved. After excavating a footage, the excavation surface is initially sprayed with 3 to 5 cm of early-strength concrete, which is weathered and loose according to the surrounding rock And the degree of spalling, the thickness of the initial shotcrete can be properly thickened as a sealing layer for subsequent grouting; then the middle step steel arch can be erected, and the circumferential radial grouting can be applied in stages or simultaneously according to the site conditions The catheter and the anchoring anchor pipe are injected with the grouting material of the present invention, and then the reinforced mesh is hung; finally, the concrete is sprayed to the design thickness to form the initial supporting structure in the middle.

(3) Step down construction

Excavate down the steps on both sides, and reserve the core soil part of the down steps. After excavating one foot, the surface of the excavation will be sprayed with 3 to 5 cm of early-strength concrete, which can be thickened appropriately according to the weathering, looseness and spalling of the surrounding rock. The shot thickness of the initial shot concrete is used as the sealing layer for the subsequent grouting work; then the lower step steel arch is erected, and according to the site conditions, it can be used as a circular radial grouting pipe and injected into the grouting of the present invention in stages or simultaneously The material is then laid with a reinforced mesh; finally the concrete is re-sprayed to the designed thickness to form the initial supporting structure at the lower part.

Compared with the general grouting material for tunnel engineering (common portland cement paste), the grouting material involved in the present invention has the following advantages and innovations:

(1) High strength and fast hardness. Aiming at the characteristics of large deformation disasters in weak and loose broken stratum tunnels, the high-strength and fast-hardening properties of stratum grouting reinforcement and anchor grouting reinforcement are fully realized, which can effectively play the role of reinforcement and suspension in time. Application, the effect is extremely significant.

(2) Simple and practical, easy to operate. The grouting material involved in the present invention uses ordinary portland cement and fast-hardening sulfoaluminate gelling agent as the cementing material, and the purpose of early strength and fast-hardening is achieved by the fast-hardening sulfoaluminate gelling agent. Salt cement controls the flow and setting time of the slurry; the on-site feeding and mixing of the tunnel is simple and the operability is strong, which can greatly improve the accuracy of the batching and the efficiency of grouting.

(3) Good penetration and high calculus rate. The grouting material involved in the present invention can be fully pressed into the surrounding rock joint cracks, and the stone formation rate is high, which can effectively play the role of strengthening surrounding rock.

(4) Economical price, suitable for promotion. The grouting material involved in the present invention meets the test and engineering requirements, compared with other chemical slurries or pure fast-hardening sulfoaluminate gelling agents, by adding ordinary Portland cement, the early strength is achieved On the basis of the purpose of fast hardening and accurate control of the slurry setting time, it greatly saves the cost (or the amount of fast hardening sulfoaluminate gelling agent), the price is economical, and it is easy to promote.

The above is a further detailed description of the method of the present invention in conjunction with specific embodiments, and it cannot be assumed that the specific implementation of the method of the present invention is limited to this. For those of ordinary skill in the technical field to which the present invention belongs, several equivalent substitutions or obvious modifications are made without departing from the concept of the present invention, and the performance or use are the same, all should be regarded as belonging to the claims submitted by the present invention The scope of protection determined by the book.

Claims (8)

1. An economical high-strength fast-hardening grouting material, which is characterized by including ordinary portland cement, fast-hardening sulfoaluminate gelling agent and water; wherein the quality of water is the same as ordinary portland cement and fast-hardening sulfoaluminate The total mass ratio of salt gelling agent is 0.46:1, the mass ratio of fast-hardening sulfoaluminate gelling agent and ordinary portland cement is (0.67～1.5):1; the initial setting time of the grouting reinforcement material It is 40±5min, and the average compressive strength of the cube after solidification for 4h is ≥10MPa.
2. The economical high-strength fast-hardening grouting material according to claim 1, characterized in that the fast-hardening sulfoaluminate gelling agent is fast-hardening sulfoaluminate 425# cement.
3. The economical high-strength fast-hardening grouting material according to claim 1 or 2, characterized in that the mass ratio of fast-hardening sulfoaluminate cement to ordinary portland cement is (1~1.5):1.
4. The economical high-strength fast-hardening grouting material according to claim 1, characterized in that the mass ratio of fast-hardening sulfoaluminate cement to ordinary portland cement is (0.67~1):1.
5. The economical high-strength fast-hardening grouting material according to claim 1, characterized in that the mass ratio of fast-hardening sulfoaluminate cement to ordinary portland cement is (0.67~0.9):1.
6. The economical high-strength fast-hardening grouting material according to claim 1, characterized in that the mass ratio of fast-hardening sulfoaluminate cement to ordinary portland cement is 1.5:1.
7. A grouting reinforcement method for a soft rock tunnel, characterized in that after excavation of the soft rock tunnel by one foot, the concrete is initially sprayed, the steel arch is erected, and the leading grouting small pipe, the circumferential radial pipe and the lock foot anchor are passed The surrounding rock is reinforced by the pipe; the advanced grouting small pipe, the circumferential radial pipe and the locking foot anchor pipe are filled with the economic high-strength fast-hard grouting material according to any one of claims 1-6; wherein The grouting pressure of the leading grouting small pipe is 1.0～3.0MPa, the grouting pressure of the circumferential radial pipe is 1.5～5.0MPa, and the grouting pressure of the lock foot anchor pipe is 0.5～1.0MPa, to achieve the opening of short time interval Digging construction.
8. The grouting reinforcement method for a soft rock tunnel according to claim 7, characterized in that the soft rock tunnel is excavated by mechanical and/or weak blasting construction methods.

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